Electrophotographic photosensitive members to be mounted on electrophotographic apparatuses include organic electrophotographic photosensitive members containing an organic photoconductive substance (hereinafter, also referred to as an “electrophotographic photosensitive member”). The organic electrophotographic photosensitive members are currently a mainstream as an electrophotographic photosensitive member used in a process cartridge for the electrophotographic apparatus or the electrophotographic apparatus, and produced in a large scale. Among these electrophotographic photosensitive members, a laminate type electrophotographic photosensitive member is often used, of which properties are improved by separately providing the functions necessary for the electrophotographic photosensitive member in individual layers.
A method of producing the laminate type electrophotographic photosensitive member is usually used in which a functional material is dissolved in an organic solvent to prepare an application solution (coating solution), and the coating solution is applied onto a support. Among the layers in the laminate type electrophotographic photosensitive member, a charge transporting layer often demands durability. For this reason, the charge transporting layer has a film thickness of a coat relatively thicker than those of other layers. Accordingly, a large amount of the coating solution is used for the charge transporting layer, resulting in a large amount of the organic solvent to be used. In order to reduce the amount of the organic solvent to be used in production of the electrophotographic photosensitive member, the amount of the organic solvent to be used for the coating solution for a charge transporting layer is desirably reduced. To prepare the coating solution for a charge transporting layer, however, a halogen solvent or an aromatic organic solvent needs to be used because a charge transporting substance and a binder resin are highly soluble in the halogen solvent or the aromatic organic solvent. For this reason, the amount of the organic solvent to be used is difficult to reduce.
PTL 1 discloses an attempt to reduce a volatile substance and the amount of an organic solvent to be used in a coating solution for forming a charge transporting layer (coating solution for a charge transporting layer). PTL 1 discloses preparation of an emulsion type coating solution (emulsion) by forming an organic solution into oil droplets in water in which the organic solution is prepared by dissolving a substance included in a charge transporting layer in an organic solvent.